1. Field of the Invention
The present invention relates to fuel usage monitoring devices for electric motor operated heating systems and also to devices for detecting the occurrence of abnormal operations occurring in the operation of such systems.
2. Description of Related Art
It has been found desirable to monitor the operation of fuel heating systems such as oil fueled heating systems to keep track of the amount of fuel consumed and the amount of fuel remaining in the heating system fuel supply tank in order to prevent a heating outage. This becomes necessary since the fuel supply tank must be refilled periodically to ensure that an adequate supply of fuel is always available when needed. The decision to refill the fuel supply tank has been made traditionally by the fuel dealer based on historical usage and on recent weather conditions. Also, the decision to refill generally has been made by using estimates based on solely “degree days” that define probable fuel usage based on the record of daily outdoor temperatures. These approaches have been found to be imprecise and can cause in multiple deliveries resulting in increased dealer delivery costs both in terms of time and energy expenditures.
Alternative approaches have involved the use of devices installed or attached to a fuel supply tank such as fuel flow devices which measure the amount of fuel remaining in the fuel supply tank and provide manual or automatic reporting of such information to the fuel dealer. Examples of these types of systems include: U.S. Pat. No. 5,619,560 to Shea issued on Apr. 6, 1997; U.S. Pat. No. 5,515,297 to Bunning issued on May 7, 1966; U.S. Pat. No. 5,063,527 to Price et al issued on Nov. 5, 1991; U.S. Pat. No. 4,845,486 to Knight issued 1984; U.S. Pat. No. 5,885,067 to Jang issued in 1997; U.S. Pat. No. 5,511,411 to Zegray issued in 1996; U.S. Pat. No. 7,305,875 to Pindus et al issued on Dec. 11, 2007; U.S. Pat. No. 7,533,703 to Shuey issued on May 19, 2009 and U.S. Pat. No. 4,296,727 to Bryan issued on Oct. 27, 1981.
Another approach utilized involves collecting and recording fuel consumption data and reporting the recorded data to a remote central monitoring site. Using historical data of fuel deliveries and consumption and sensor supplied running information received from microprocessor devices installed at user heating system site locations, the remote central site system computes the fuel consumption and determines when the microprocessor devices should call and report again. Examples of this approach can be found in U.S. Pat. No. 6,023,667 to Johnson issued on Feb. 8, 2000 and U.S. Pat. No. 7,229,278 to Newberry issued on Jun. 12, 2007. It has been found that this approach still lacks some imprecision and can prove costly to heating system users.
Additionally, other approaches such as those of Humphrey described in U.S. Pat. No. 7,295,919 issued on Nov. 13, 2007 and patent applications 20060243347 and 20080033668 published on Nov. 2, 2006 and Feb. 7, 2008 respectively to disclose a system for delivering propane or other consumable liquid to remotely located storage tanks that provides remote monitoring of customer tanks and a method of using the remote monitoring data to optimally schedule deliveries, improve safety, and more efficiently operate a propane dealership. Such approaches provide solutions that are not directly applicable to heating systems that are electronically driven.